Re: Problems with map(function, array)

[tobyink]

Nothing to do with map really. uc has magic!

In the following construct, uc is getting called with no parameters:

my @caps = map uc, @lower;

As per perlfunc, when called with no parameters, uc operates on $_. So you need to make your function act the same (as indeed you did in your second experiment).

From Perl 5.10 and above, there's a better technique to write such functions:

sub my_uc (_) {  # note underscore in parentheses
  my $c = shift;
  return uc($c);
}

And now my_uc has the same magic as uc.

[Redei]

Thank you very much. That is just what I needed. Now, instead of

sub twice { 2 * (shift // $_) }

I'll use something like

sub twice(_) { 2 * shift }